In a typical wireless communication network, wireless devices, also known as mobile stations and/or user equipments (UEs), communicate via a Radio Access Network (RAN) to one or more core networks (CN). The RAN covers a geographical area which is divided into cell areas, with each cell area being served by a base station, e.g., a radio base station (RBS), which in some networks may also be called, for example, a “NodeB” or “eNodeB” (eNB). A cell is a geographical area where radio coverage is provided by the radio base station at a base station site or an antenna site in case the antenna and the radio base station are not collocated. Each cell is identified by an identity within the local radio area, which is broadcast in the cell. Another identity identifying the cell uniquely in the whole wireless communication network is also broadcasted in the cell. One base station may have one or more cells. The base stations communicate over the air interface operating on radio frequencies with the wireless devices within range of the base stations.
A Universal Mobile Telecommunications System (UMTS) is a third generation mobile communication system, which evolved from the second generation (2G) Global System for Mobile Communications (GSM). The UMTS terrestrial radio access network (UTRAN) is essentially a RAN using wideband code division multiple access (WCDMA) and/or High Speed Packet Access (HSPA) for wireless devices. In a forum known as the Third Generation Partnership Project (3GPP), telecommunications suppliers propose and agree upon standards for third generation networks and UTRAN specifically, and investigate enhanced data rate and radio capacity. In some versions of the RAN as e.g. in UMTS, several base stations may be connected, e.g., by landlines or microwave, to a controller node, such as a radio network controller (RNC) or a base station controller (BSC), which supervises and coordinates various activities of the plural base stations connected thereto. The RNCs are typically connected to one or more core networks.
Specifications for the Evolved Packet System (EPS) have been completed within the 3rd Generation Partnership Project (3GPP) and this work continues in the coming 3GPP releases. The EPS comprises the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), also known as the Long Term Evolution (LTE) radio access, and the Evolved Packet Core (EPC), also known as System Architecture Evolution (SAE) core network. E-UTRAN/LTE is a variant of a 3GPP radio access technology wherein the radio base stations are directly connected to the EPC core network rather than to RNCs. In general, in E-UTRAN/LTE the functions of a RNC are distributed between the radio base stations, called eNodeBs in LTE, and the core network. As such, the Radio Access Network (RAN) of an EPS has an essentially “flat” architecture comprising radio base stations without reporting to RNCs.
Furthermore, EPC is made up of several nodes including a Mobility Management Entity (MME) which communicates with the eNodeBs in E-UTRAN over the S1-MME interface and with a Serving GateWay (S-GW) in the EPC over the S11 interface. The S-GW communicates with the Packet Data Network-GateWay (PDN-GW) over the S5 interface. The control plane part of S5 and S11 is using General Packet Radio Service Tunneling Protocol-Control Plane (GTP-C) version 2 protocol, while the S1-MME uses the S1-Application Protocol (AP). The communication over these interfaces is either node related or wireless device related. In case it is wireless device related specified identifiers are used to associate the signalling messages with the wireless device connection. Over S1-AP an MME UE S1AP Identity (ID) and an eNB UE S1AP ID are used. Over S5 and S11 a Control Tunnel Endpoint Identifier (TEID) is used. These IDs are allocated and used as long as the 51 and S5/S11 wireless device connection exists and can only be changed for new connections. In addition to these identifiers also identifiers known in the wireless device are used such as the International Mobile Subscriber Identity (IMSI), International Mobile Station Equipment Identity (IMEI) and Packet-Temporary Mobile Subscriber Identity (P-TMSI) or SAE-Temporary Mobile Subscriber Identity (S-TMSI).
In a typical product implementation in a network node such as the MME, as well as the eNB, S-GW, PDN-GW, context identifiers are used to route messages or control messages to a right processing module, such as a processing board or virtual machine emulating a processing board or part of a processing board, which has the context of the wireless device and terminates all wireless device related signalling. This works since the context identifiers of the wireless device are different in different directions so that each side can dictate how they want the context of the wireless device to be addressed. Context of a wireless device comprises e.g. different identities such as wireless device identity and cell identity serving the wireless device, radio bearer information associated to the wireless device, mobility management state, location information of the wireless device and similar.
Since the current identifiers used over S1, S11, and S5, such as the MME UE S1AP ID, and the TEIDs used in GTP-C are allocated for the whole connection, S1 UE signalling connection over S1, and as long as there are any UE bearers over S5, S11, it is not possible to quickly change the processing module that handles a specific wireless device related message, assuming these identities are also used for internal routing in the receiving node. This means that the same processing module needs to handle the same context of the wireless device for a long period, which could make it difficult to load share been processing modules, i.e. change load between processing modules, or load share when adding or removing a processing module. This results in an inefficient handling of signalling procedures with the static use of the same processing module for signalling procedures for a certain wireless device.